Wireless mesh network (WMN) are useful in many applications because of their low up-front costs, flexibility in incremental deployment and ease of maintenance. For example, WMN are widely used in community networks, enterprise networks, video surveillance, voice communications and localization services. Wireless mesh network architecture is often seen as a first step towards providing cost effective and dynamic high-bandwidth networks over a specific coverage area. A wireless mesh network can be seen as a special type of wireless ad-hoc network using IEEE 802.11 ad-hoc protocol for backbone infrastructure. A wireless mesh network often has a more planned configuration, and may be deployed to provide dynamic and cost effective connectivity over a certain geographic area. An ad-hoc network, on the other hand, is formed ad hoc when wireless devices come within communication range of each other.
However, WMN are vulnerable to throughput degradation due to their multi-hop nature, and such throughput degradation is due primarily to contention or half-duplex communication in single-radio networks. This is because an access node with a single wireless interface cannot transmit and receive packets simultaneously—it must first receive and then transmit in order to relay a packet. The channel time required to relay a packet is thus at least twice the amount of time for sending a packet directly from the source to the destination. Moreover, the carrier-sensing mechanism in IEEE 802.11 MAC may prevent simultaneous transmissions on the same channel, and radio interference (or collision) may occur when the carrier sensing fails to prevent interfering links from transmitting simultaneously. These will all affect the multi-hop throughput performance and hence limit the coverage of WMN.